22 BOTANY. ' black bed of vegetable mould, on which a heavy sward is found. This probably would indicate, as the appearance of the surrounding country tends to confirm, that water may be had here at no great depth. Indeed, it appeared as though part of the season this especial area might be rather swampy. From Zuni south, the country may be regarded as sloping toward the Colorado Chiquito, and fairly merits the designation of "a dry rolling country". Thence south it again ascends to the White Mountains of Ari¬ zona, a densely timbered range, culminating in Mount Ord, 10,266 feet high, and Mount Thomas, 11,496 feet high. The road to Camp Apache crosses it at an elevation of about 7,400 feet; Willow Spring, somewhat lower, gives an altitude of 7,195 feet. Here the scene was one of transcendent floral wealth. The ordinary coniferous growth, to which we have already alluded, mixed in about equal proportions with Quercus undulata. The Conifers towered up sometimes more than a hundred feet, but the Oaks were seldom over 25 feet high, but branched out vigorously. The declivities of this range are deeply cut by canons extending out from the centre like so many radii of a great circle. The soil is largely made up from di^ntegra- tion of volcanic rocks. The herbaceous vegetation was luxuriant beyond anything elsewhere seen in Arizona, and here only was the striking Sisyrin- chium Arizonicum found. Frasera speciosa, Onosmodium Thurberi, and acres of Aqiiilegia chrysantha, luxuriated on the hill-sides; whilst in the cold spring- water Claytonia Chamissonis, Ranunculus hydrocharoides, and Habenaria leucos- tachys were growing abundantly. Though in Arizona, these mountains are deeply covered -with snow each winter, so much so as to practically serve as barriers, the dense growth of timber seen on them is simply a portion (possibly the best por¬ tion) of a belt extending from old Camp Tulerosa westward to Camp Verde, a distance of about three hundred miles. It is known under the general designation of the Black Mesa, or the Mogollon Mesa. It is really an island of verdure raised up out of the more desert areas north and south of it. Its average width is not great. " The Carboniferous strata predominate, but the southern extension is covered by basaltic eruptions."* * Loew, vol. iii, Wheeler's Eeport, p. 587.